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This paper proposed one novel Thermo-Electric Ventilation (TEV) system driven by the concentrated photovoltaic-thermoelectric generator (CPV-TEG), which could use the electric power converted directly from solar energy by CPV-TEG. The effects of incident solar irradiance, number of thermoelectric generators, and ambient air temperatures on the power output of CPV-TEG have been analytically investigated through energy balance and first law of thermodynamics. Furthermore, input current and number of thermoelectric coolers were sensitively varied to optimize the performance of TEV system respectively in heating and cooling modes. Finally, an integrated theoretical and numerical approach was proposed to match the power output of CPV-TEG with the power input of TEV. Modeling results indicate that the output power from CPV-TEG could satisfy the energy demand of TEV system when the input currents of thermoelectric coolers were no more than 2.5 A and 2.8 A respectively for cooling and heating modes. Minimum energy and exergy efficiencies of the system in winter heating mode were confirmed to be 1.67 and 0.24 respectively, which were far higher than that in summer cooling mode. This research may be helpful for enhancing performance and reducing exergy destruction of thermoelectric ventilation system, simultaneously.

In this study, based on Smoothed Particle Hydrodynamics (SPH) and Discrete Element Method (DEM), a multiphase fluid-solid coupling algorithm of SPH-DEM is provided, and a high performance coupling module is developed based on two open-source software platforms, namely: DualSphysics for SPH and Blaze-DEM for DEM. With a comparative analysis of three typical tests, it is systematically proved that the developed coupling module can feasibly and precisely tackle the complex coupling between solid particles and fluid. Moreover, based on the test results of single particle sedimentation and water-entry of spinning spheres, three water-entry stages of the spheres are characterized: contact and shockwave generation, cavity formation and water splashing, and cavity closure and collapse. As a complex problem, the submerged granular collapse is simulated, and according to the numerical results the process of granular collapse can be divided into four stages: beginning, collapsing, decelerated sliding and stable sedimentation. The granular aggregation can be partitioned into the zones of flowing, sliding, shearing, and relatively standstill particles by the motion characteristics of different parts of particles on different stages. In addition, the macro- and meso-characteristics of the process of granular collapse are also discussed. According to the research results of this study, the developed SPH-DEM module can better simulate the complex coupling process between fluid and granular materials. Furthermore, with more information obtainable, numerical simulation is important to get insight into this process.

Two categories of thermoelectric systems, i.e. thermoelectric active cooling (TAC) and thermoelectric self-cooling (TSC), were broadly applied for electronic cooling. Energy efficiency maximization and entropy generation minimization will be simultaneously achieved for both thermoelectric systems. Thermodynamic models of TAC and TSC systems are established to clarify the effects of main influencing parameters (i.e., applied current, thermal conductance in hot and cold ends) on the energy and entropy performances. Subsequently, under the situation of electronic cooling with constant material properties, a comprehensive performance comparison between TAC and TSC has been conducted, including decision targets, irreversible characteristics and environmental impacts. Furthermore, in order to improve the heat dissipation potential, the effects of material properties on the system performance are also sensitively identified for both TAC and TSC systems. For both systems, internal irreversibility is more pronounced than external one. Numerical results demonstrated that system efficiency of TAC could be higher than that of TSC; the operating mode for TAC could be completely switched to that for TSC when the input power was turned into zero. Present investigation could give suitable guidelines for thermoelectric systems applied for electronic cooling.

An active thermoelectric ventilated (ATEV) system coupling with multiple thermoelectric coolers and heat sinks was proposed in the present work. Depending on global energy balance and finite time thermodynamics, performance parameters were firstly presented, including cooling capacity, entropy generation and coefficient of performance (COP). Subsequently, two analytical sub-models respectively for parallel flow heat exchangers and counter flow ones were developed. Input current of thermoelectric coolers, quantitative numbers of thermoelectric coolers and two heat exchanger types (parallel and counter flows) were sensitively varied to optimize overall performance of this system. In a representative residential space, demo case comparisons between traditional thermoelectric cooling units and present ATEV system have been conducted. When the number of thermoelectric coolers exceeded eight, cooling capacity of this new system decreased remarkably. For parallel flow heat exchangers, the entropy generation rate (Sg) firstly dropped and then started to increase; for counter flow heat exchangers, whereas, it continuously decreased with increasing unit cell numbers. Overall, present ATEV system integrating built envelope wall and thermoelectric modules simultaneously could be a promising technology to enhance space cooling, whatever for built residents or electronic facilities.

Fluid-solid coupling is a common phenomenon in the studies of granular materials, geotechnical engineering and so on. Based on a multiphase fluid model in the framework of lattice Boltzmann method (LBM) and the discrete element method (DEM), a multiphase fluid-solid coupling algorithm of LBM-DEM is proposed, where the coupling module is developed on the basis of two open-source codes, Palabos and Yade. The feasibility and accuracy of the algorithm are validated through three classical fluid-solid coupling examples: a single sphere settling in a fluid, a sphere falling into a fluid from the air and two spheres colliding with each other in fluid. Then two complex phenomena in geotechnical engineering, transient-state flow and debris flow, are simulated. The results indicate that the LBM-DEM coupled method has strong advantages in the numerical simulation of complex fluid-solid coupling problems. It can accurately reveal the fluid-solid interaction mechanisms, physical & mechanical behaviors and failure process at both macroscopic and mesoscopic scales. Furthermore, from the numerical simulation results, the process of debris flow can be divided into three stages: steady seepage stage, startup stage and flow stage of the fluid-solid mixture.

For further comprehending the mechanism of the intensification of ultrasound for extraction, the difference of leaching kinetics between the ultrasound-assisted and conventional sodium carbonate leaching of scheelite was studied, and the corresponding kinetic equations were established. The results indicate that the obtained apparent activation energy with or without ultrasound is same 72 kJ/mol, and both reactions are controlled by surface chemical reaction. By comparing the leaching kinetics of scheelite by Na2CO3, NaOH and Na3PO4 reactants with or without ultrasound, a general conclusion for scheelite hydrometallurgy is obtained. For the process with the formation of compact product layer, the intensification of the tungsten extraction with ultrasound mainly reflects in the stripping and elimination of product layer, corresponding to the transformation of kinetic controlling step from diffusion controlling step and reduction of apparent activation energy. For the one without compact product layer or with a loose and porous product layer, the intensification mainly embodies in the increase of frequency factor, and the controlling step and apparent activation energy of the reaction always remain constant.

We have investigated whether simultaneous modification of cofactor metabolism and glycerol in a strain of Saccharomyces cerevisiae can eliminate glycerol synthesis during ethanol production. Two strains, S812 (gpd1Δ gpd2Δ PGK1p-GLT1) and LE17 (gpd1Δ gpd2Δ PGK1p-GLT1 PGKp-STL1) were generated that showed a 8 and 8.2 % increase in the ethanol yield, respectively, compared to the wild type KAM-2 strain. The ethanol titer was improved from 90.4 g/l for KAM-2 to 97.6 g/l for S812 and 97.8 g/l for LE17, respectively. These results provide a new insight into rationalization of metabolic engineering strategies for improvement of ethanol yield through elimination of glycerol production.

The recombinant xylose-fermenting Saccharomyces cerevisiae strain harboring xylose reductase (XR) and xylitol dehydrogenase (XDH) from Scheffersomyces stipitis requires NADPH and NAD + , creates cofactor imbalance, and causes xylitol accumulation during growth on d -xylose. To solve this problem, noxE , encoding a water-forming NADH oxidase from Lactococcus lactis driven by the PGK1 promoter, was introduced into the xylose-utilizing yeast strain KAM-3X. A cofactor microcycle was set up between the utilization of NAD + by XDH and the formation of NAD + by water-forming NADH oxidase. Overexpression of noxE significantly decreased xylitol formation and increased final ethanol production during xylose fermentation. Under xylose fermentation conditions with an initial d -xylose concentration of 50 g/liter, the xylitol yields for of KAM-3X(pPGK1-noxE) and control strain KAM-3X were 0.058 g/g xylose and 0.191 g/g, respectively, which showed a 69.63% decrease owing to noxE overexpression; the ethanol yields were 0.294 g/g for KAM-3X(pPGK1-noxE) and 0.211 g/g for the control strain KAM-3X, which indicated a 39.33% increase due to noxE overexpression. At the same time, the glycerol yield also was reduced by 53.85% on account of the decrease in the NADH pool caused by overexpression of noxE .

Based on the analysis of the potential ecological risk posed by the development of industrial cities along the Second Songhua River, according to the calculated ecological risk relative values and the development in different directions, the risk control measures aimed at different cities were put forward respectively. This study is a supplement of the domestic regional ecological risk research, and has a practical significance for the research of pollution control in the Songhua River. The result shows that the potential ecological risk in Jilin section, the greatest contribution to the potential risk is the toxic organic pollutants and heavy metals in sediments; the potential ecological risk in Songyuan section is slightly higher than that in front of the Fengman dam, the greatest contribution to the potential risk in Songyuan section is water pollution.

Glycerol is a major by-product in bioethanol fermentation by the yeast Saccharomyces cerevisiae , and decreasing glycerol formation for increased ethanol yield has been a major research effort in the bioethanol field. A new strategy has been used in the present study for reduced glycerol formation and improved ethanol fermentation performance by finely modulating the expression of GPD1 in the KAM15 strain ( fps1 Δ pPGK1-GLT1 gpd2 Δ). The GPD1 promoter was serially truncated from the 3′ end by 20 bp to result in a different expression strength of GPD1 . The two engineered promoters carrying 60- and 80-bp truncations exhibited reduced promoter strength but unaffected osmostress response. These two promoters were integrated into the KAM15 strain, generating strains LE34U and LE35U, respectively. The transcription levels of LE34U and LE35U were 37.77 to 45.12% and 21.34 to 24.15% of that of KAM15U, respectively, depending on osmotic stress imposed by various glucose concentrations. In very high gravity (VHG) fermentation, the levels of glycerol for LE34U and LE35U were reduced by 15.81% and 30.66%, respectively, compared to KAM15U. The yield and final concentration of ethanol for LE35U were 3.46% and 0.33% higher, respectively, than those of KAM15U. However, fermentation rate and ethanol productivity for LE35U were reduced. On the other hand, the ethanol yield and final concentration for LE34U were enhanced by 2.28% and 2.32%, respectively, compared to those of KAM15U. In addition, a 2.31% increase in ethanol productivity was observed for LE34U compared to KAM15U. These results verified the feasibility of our strategy for yeast strain development.

To evaluate the safety and efficacy of transanal drainage tube followed by laparoscopic surgery in management of malignant colorectal obstruction.From March 2007 to October 2010, 37 patients with colorectal cancer manifesting acute complete mechanical obstruction were treated by ileus tube drainage. After irrigation and drainage ranging from 4 to 10 days, the radical operations and anastomosis were performed by laparoscopy.The drainage tubes were successfully implanted in 34 patients. The decompression time of patients was (5.8 ± 1.6) d, ranging from 4 to 10 d. The abdominal pain and bloating symptoms were faded away after (3.8 ± 1.3) d (1 to 7 d) drainage. And comparing to that of patients when admission, abdominal circumference significantly reduced from (92 ± 7) cm to (84 ± 6) cm (P = 0.013) before surgery. Thirty-one cases were performed radical resection and anastomosis by laparoscopy after decompression. Postoperative recovery was smooth, and there was no serious complication.Laparoscopic surgery followed decompression by transanal ileus tube is effective and safe for acute lower colorectal obstruction. Emergency surgery may be converted to limit surgery by this method. After appropriate bowel preparation, laparoscopic radical surgery and anastomosis is feasible.

Genome shuffling is an efficient way to improve complex phenotypes under the control of multiple genes. For the improvement of strain’s performance in very high-gravity (VHG) fermentation, we developed a new method of genome shuffling. A diploid ste2/ste2 strain was subjected to EMS (ethyl methanesulfonate) mutagenesis followed by meiotic recombination-mediated genome shuffling. The resulting haploid progenies were intrapopulation sterile and therefore haploid recombinant cells with improved phenotypes were directly selected under selection condition. In VHG fermentation, strain WS1D and WS5D obtained by this approach exhibited remarkably enhanced tolerance to ethanol and osmolarity, increased metabolic rate, and 15.12% and 15.59% increased ethanol yield compared to the starting strain W303D, respectively. These results verified the feasibility of the strain improvement strategy and suggested that it is a powerful and high throughput method for development of Saccharomyces cerevisiae strains with desired phenotypes that is complex and cannot be addressed with rational approaches.